Gaya APA

Service, P, E., Contra, I, A, O, D. (1981). Lessons in rotary drilling. Unit I Lesson 10. safety on rthe rig. (1981). : Texas : Petroleum Extension Service,.

Gaya MLA

Service, Petroleum, Extension., Contra, Inter., Ass., Of, Drilling. "Lessons in rotary drilling. Unit I Lesson 10. safety on rthe rig.". 1981 : Texas : Petroleum Extension Service,, 1981. Text.